A team of international astronomers have discovered three Earth-sized planets orbiting two stars, in what researchers are calling a laboratory for studying planet formation.The finding, announced Friday in the journal Astronomy & Astrophysics, centers around the binary star system TOI-2267, located approximately 190 light-years from Earth. What makes this discovery particularly remarkable is that it represents the first known binary system where planets are passing in front of both stars.Lead researcher Sebastian Zuniga-Fernandez from the University of Liege explained the significance: “This makes TOI-2267 the first binary system known to host transiting planets around both of its stars.”The international team used Nasa’s planet-hunting TESS spacecraft to identify the three worlds, challenging long-held beliefs that binary star systems were too unstable for complex planetary arrangements. According to co-researcher Francisco J Pozuelos, the discovery shatters multiple assumptions about planetary formation.“Our discovery breaks several records, as it is the most compact and coldest pair of stars with planets known, and it is also the first in which planets have been recorded transiting around both components,” Pozuelos explained.He described the system as “a true natural laboratory for understanding how rocky planets can emerge and survive under extreme dynamical conditions, where we previously thought their stability would be compromised.”The researchers emphasised that this discovery is more than just a new finding; it opens entirely new avenues for understanding planet formation. Fernandez noted that the compact binary system provides a unique opportunity and added “It allows us to test the limits of planet formation models in complex environments and to better understand the diversity of possible planetary architectures in our galaxy.”